In this paper we have investigated the MIR expressed by AM colonized plants against the vascular pathogen Fusarium oxysporum f sp lycopersici. The mechanism of resistance to this vascular pathogen has been reported to be mediated either by SA and/or JA/ ET pathway. An SA deficient mutant sid2 of Arabidopsis as well as a JA insensitive mutant jai1 in tomato showed increased susceptibility to F. oxysporum